*t7.5>' 


\|>ril  23,  1910. 


U.  S.  DEPARTMENT  OF  AGRICULTURE. 

BUREAU  OF  ENTOMOLOGY— CIRCULAR  No.  118. 

L.  O.  HOWARD.  Entomologist  and  Chief  of  Bureau. 


A  PREDACEOUS  MITE  PROVES  NOXIOUS  TO  MAN. 

(Pedicvioides  ventricosus  Newport.) 


F.  M.  WEBSTER, 

TnChargi  of  Cereal  and  Foragt  Insect  Investigations. 


WASHINGTON    :  GOVERNMENT  PRINTING  OFFICE   :    '»IO 


BUREAU  OF  ENTOMOLOGY. 

L.  O.  Howard,  Entomologist  and  Chief  of  Bureau. 

G.  L.  Marlatt,  Assistant  Entomologist  and  Acting  <  'hiefin  Absence  of  Chief . 
R.  S.  Clifton,  Executive  Assistant. 
Chas.  J.  Gilliss,  ( 'hief  <  'lerh. 

F.  H.  Chittenden,  in  charge  of  truck  crop  and  stored  product  insect  inrestigations. 

A.  D.  Hopkins,  in  charge  of  forest  insect  investigations. 

W.  D.  Hunter,  in  charge  of  southern  field  crop  insect  investigations . 

F.  M.  Webster,  in  charge  of  cereal  and  forage  insect  investigations. 

A.  L.  Quaintance,  in  charge  of  deciduous  fruit  insect  investigations. 

E.  F.  Phillips,  in  charge  of  bee  cultun  . 

D.  M.  Rogers,  in  charge  of  preventing  spread  of  moths,  field  work. 

Rolla  P.  Currie,  in  charge  of  editorial  work. 

Mabel  Colcord,  librarian. 

Cereai  and  Forage  Insect  Investigations. 

F.  M.  Webster,  in  charge. 

Geo.  I.  Reeves,  W.J.  Phillips,  C.  N.  Ainslie,  E.  0.  G.  Kelly,  J.  A.  Hyslop, 
V.  L.  Wildermuth,  K.  A.  Vickery,  T.  11.  Parks,  Herbert  Osborn,  I'iiii  111 
Luginbill,  agents  and  experts. 

(II) 
[Cir.    118] 


Circular  No.  1 18. 


Issued  April  . 


United  States  Department  of  Agriculture, 

BUREAU   OF    ENTOMOLOGY, 
L.  O.  HOWARD,  Entomologist  and  Chief  of  Bureau. 


A  PREDACEOUS   MITE   PROVES    NOXIOUS  TO   MAN. 

(Pediculoidt  s  Newport 

Bj   F.  M.  Wi  bst] 
I    i  biuiji  of  Cereal  and  Forage  Insect  Investigations. 

INTRODUCTION. 

While  the  scientific  and  medical  literature  of  European  countries, 
ami  to  some  extent  of  Asiatic  countries)  contains  numerous  records 
of  mites  attacking  man,  ii  is  difficull  to  determine,  from  a  perusal 
of  this  literature,  whether  <>r  ool  the  mite 
Pediculoides  ventricosus  Newport,  shown  in 
iu  mosl  active  form  \>\  figure  1,  has  Keen 
concerned  in  these  attacks.  There  i-  no 
particular  reason  why  it  should  not  have 
become  noxious  i<>  man  precisely  as,  and 
elsewhere  than,  in  America,  because  ii  has 
doubtless,  with  it-  hosl  insect,  the  Angoumois 
grain  moth,  Sitotroga  cerealeUa  Oliv.  (fig.  3), 
been  distributed  in  grains  throughout  the 
warm  regions  of  the  globe,  wherever  these 
grains  have  entered  into  international  com- 
merce. While  there  is  a  derided  similarity 
between  these  attacks  on  man  in  Europe  and 
America,  the  writer  is  unable  to  select,  from 
the  various  instances  recorded,  a  single  one  in 
which  lie  can  unhesitatingly  -a\  thai  tins  and 
nol  some  other  species  of  mite  was  responsi- 
ble for  such  at  tack-.  In  iii.-in  \  casesil  is  very 
clearlj  to  l>e  seen  thai  other  and  very  differ- 
ent species  of  mites  have  been  involved  in  at  tacks  of  a  similar  nature, 
both  in  this  country  and  in  Europe.     Mere  in  America  such  troubles 

L18] 

(1) 


Fig.  I.  \duli  female  of  Pedicu- 
loides l  111'  ali- 
domen  has  become  inflated  with 
eggs  and  young.  In  tin 
(ion  the  mite  is  nomadic  and 
predatory.  Greatly  enlarged, 
drawn  from  Brack 


have  until  recently  been  commonly  attributed  to  "chiggers,"a  winch 
inhabit  neither  the  dried  straw  nor  thrashed  grain.  The  term  "  cliig- 
ger"  really  includes  a  number  of  different  kinds  of  mites,  notably  the 
young  of  Trombidium  and  other  insects  which  inhabit  grassy  and 
weedy  places  and  woodlands.  This  is  why  it  is  that  people  visiting 
such  places  are  not  infrequently  attacked  and  suffer  painfully  there- 
from. While  our  knowledge  of  the  matter  remained  in  this  condi- 
tion, the  possibility  of  confusing  the  disease  discussed  herein  with 
others  of  a  much  more  serious  nature  was  very  great,  but  now  that 
we  understand  the  causes  and  know  that  these  causes  can  be  re- 
moved, and  the  physician  enabled  to  distinguish  it  from  an  attack 
of  "chiggers"  and  prescribe  proper  treatment,  much  of  this  danger 

and  painful  annoyance  may 
be  eliminated.  There  is  also 
another  point  that  must  not 
be  overlooked,  namely,  that 
this  mite  during  its  period  of 
greatest  activity  is  almost  in- 
visible to  the  unaided  eye  (see 
fig.  1).  Not  every  practicing 
physician  possesses  a  micro- 
scope that  will  enable  him  to 
detect  the  presence  of  the 
mite,  even  when  abundant, 
but  the  pustules  or  wheals 
caused  by  it  are  sufficiently 
described  in  the  paper  by  Doc- 
tors Goldberger  and  Scham- 
berg  and  the  one  by  Doctor 
Rawles  to  permit  of  identifica- 
tion. Later,  when  the  gravid 
female  mite  (fig.  2)  is  dis- 
tended with  eggs  and  young, 
it  is  more  easily  detected;  hut  it  is  not  in  this  state  that  if  attacks 
human  beings  and  is  thus  encountered   by  tin1  practicing  physician. 

THE    MITE    BENEFICIAL    IN     AMERICA. 

So  far  as  (he  author  lias  been  able  t<>  determine,  the  first  pub- 
lished record  of  the  occurrence  of  this  mite  in  America  was  by  him- 
self, and  was  included  in  a  paper  printed  in  the  Twelfth  Reporl 
of  the  Slate  Entomologist  of  Illinois  (pp.  1  oO-lol ).''  While  assistant 
to  Dr.  S.  A.  Forbes,  stale  entomologist,  he  was  directed  to  investi- 
gate serious  injuries  to  stored  grain  by  the  Angoumois  grain  moth, 

"  For  aeon  ideration  of  "chiggers,"  see  Circular  No.  77,  Bur.  Ent.,  pp.  1-6. 
b  Publi  bed  in  Trans.  Dept.  Agr.  Illinois,  vol.  20,  1882. 
[Cir.    118] 


Fig.  2.     ( a  avid  female  of  Pediculoidcs  vi  ntricosus.  Greatly 
enlarged.    (Redrawn  from  Brucker.) 


Sitotroga  <■<  realeUa  (fig.  3  i,  in  southern  [llinois,  where  Messrs.  I  [alliday 
Brothers,  of  Cairo,  growers  and  shippers  of  wheat,  were  al  thai  time 
experiencing  considerable  trouble  from  the  ravages  of  ihis  grain 
moth,  inn  « . 1 1 1 \  in  their  grain  elevators  bul  also  in  barges  loaded 
with  wheal  to  be  shipped  by  river  to  New  Orleans  and  thence  exported 
by  steamer. 

It  was  during  these  investigations  thai  this  mite  was  discovered 
attacking  the  larvae  of  the  grain  moth.  As  the  original  publication 
containing  the  author's  observations  is  becoming  more  and  more 
difficult  i"  obtain,  thai  portion  relating  to  the  occurrence  of  this 
mite  is  given  here\n  ii  h  in  full : 

Pedicukndes  [Heteropus)  i     is,  Newport.     About  iho  12th  of  October,   1882, 

a  sack  of  wheal  infested  with  larva;  of  the  grain  moth  was  received  from  southern 
[llinois,  which,  for  wanl  of  time,  was  put  aside  for  future  inspection,     (in  the  L3th 


Fio.3.  Angoumois  grain raoth  {Sitotroga  cerealcUa):  a.  Egg  and  egg-mass; 
';,  larva  in  grain  of  wheat;  c,  larva;  (/,  pupa;  f,  /,  moth.  Enlarged. 
(i.  (■--/.  After  Chittenden;  b,  original.) 

of  November,  while  examining  the  grains  containing  larva?,  1  noticed,  in  a  lot  of 
fifty,  three  in  which  the  worms  were  dead,  ami  on  them  were  numbers  of  globular, 
yellow  objects,  which  proved  to  be  a  species  of  mite,  Pediculoides  <  Tleteropus)  ventri- 
Knowing  nothing  of  the  predaceous  habits  of  these  mites,  and  the 
limited  literature  al  hand  throwing  little  light  upon  the  matter,  1  did  not  pay  much 
attention  to  the  fact  of  their  occurrence  until  the  12th  of  December,  when  upon 
examining  LOO  grains  with  respect  to  the  effect  of  heal  on  the  larva,  I  found  M  of  the 
latter  infested  by  these  mites. 

In  the  meantime  I  had  learned  that  this  mite  was  known  to  be  of  predaceous  habit, 
in  both  England  and  France,  having  been  first  discovered  by  Newport,  in  I849,in 
the  nests  of  Anthophora  retusa,  collected  at  Gravesend,  England,  and  afterwards 
described  by  him  under  its  present  name.  Ii  had  also  been  found  in  France,  in 
ls,iS.  bj  Jules  Lichtenstein,  of  Montpellier,  and  described  by  him  under  the  name  of 
This  gentleman  found  it  in  his  breeding  cages,  which  it  so 
completi  Ij  overran  that,  as  he  informs  me,  he  could  not  for  six  months  breed  a  single 
specimen  ol  Symenoptera,  of  Bupn  r  Ceramby  of  some  Lepidoptera. 

[Clr 


If  it  has  been  found  by  any  other  persons  than  these,  or  in  any  other  parts  of  the  world, 
previous  to  its  discovery  here  by  me,  I  have  not  been  able  to  find  the  fact  recorded. 

On  December  31  and  January  1,  I  examined  100  infested  grains  of  this  wheat, 
which  had  been  continually  kept  in  the  laboratory  since  it  was  received,  and  found 
'.V2  per  cent  of  the  worms  dead,  infested  by  the  mites. 

While  making  these  examinations  I  frequently  threw  the  grains  containing  infested 
larvae  into  a  shallow  glass  dish,  where  they  remained  on  my  table  until  the  warm 
weather  during  the  latter  part  of  February,  when  the  temperature  of  the  laboratory 
at  night  was  much  higher  than  it  had  been  during  the  previous  cold  weather.  The 
effect  of  the  change  was  soon  plainly  to  be  seen.  The  contents  of  the  dish  began  to 
swarm  with  newly  developed  mites,  and  a  larva  dropped  into  their  midst  was  imme- 
diately attacked,  and  after  that  its  life  was  of  short  duration.  Larvas  placed  at  some 
distance  from  the  dish  suffered  a  like  infection. 

To  test  the  matter  I  placed  near  the  dish  some  weeds,  in  the  pith  of  which  some 
larvae  were  hibernating,  and  in  two  days  the  mites  had  found  and  destroyed  them. 
These  young  mites  when  first  m  it  iced  are  very  minute,  of  elongate  form,  and  extremely 
active,  running  about  in  search  of  larva1;  and  when  one  is  found  they  immediately 
puncture  the  skin  and  suck  the  juices. 

In  a  day  or  two  the  posterior  segments  of  the  abdomen  begin  to  enlarge,  and  this 
process  continues  until  the  inflated,  bladder-like  abdomen  becomes  ten  or  even  twenty 
times  the  size  of  the  cephalothorax. 

During  this  time  they  have  gradually  lost  their  ambulatory  powers,  and  remain 
stationary  upon  their  -victims.  In  the  meantime  changes  equally  wonderful  have  been 
going  on  within  the  abdomen. 

Eggs  are  continually  forming,  and  within  these  the  young  mites  are  as  continually 
developing,  passing  through  their  entire  metamorphosis,  which  includes  thi  acquisition 
of  the  fourth  "pair  of  legs  (an  exceptional  character  among  mites),  within  the  abdomen 
of  the  mother,  from  which  they  make  their  way  as  fast  as  they  reach  maturity. 

The  females  are  quite  prolific.  I  have  counted  frequently  from  40  to  50  young 
and  eggs  within  the  abdomen,  and  believe  thai  they  produce  even  more.  The  mothers 
survive  the  birth  of  a  large  number,  if  not  a  majority,  of  the  young.  The  male  I  have 
never  found,  and  1  am  inclined  to  believe  with  Mr.  Newport,  that  the  species  is 
parthenogenous.0  The  minute  size  (if  these  young  miles  admits  of  Iheir  free  access 
in  the  larva?  of  the  moth,  through  the  very  small  opening  where  this  made  its  entry, 
and  a  single  mite  with  its  progeny  would  be  sufficient  to  destroy  it. 

That  this  is  very  often  the  manner  of  attack  is  proved  by  the  fact  that  grains  in 
which  the  larva  is  badly  infested  frequently  have  no  other  break  in  the  hull  by  which 
evenayoung  mite  could  gain  admission.  Like  the  larvae  on  which  they  subsist,  their 
development  is  retarded  or  increased  by  the  temperature,  they  being  quite  active  at 
a  temperature  of  00°  F.;  but  in  colder  weather  able  to  remain  within  the  abdomen 
of  the  parent  for  months  in  a  dormant  state,  awaiting  a  rising  temperature. 

While,  as  stated,  this  was  probably  the  first  published  record 
of  the  occurrence  of  this  Pediculoides  in  America,  the  writer  has 
since  had  reason  to  believe  that  it  was  present  many  years  prior  to 
this  date;  and,  indeed,  in  t  he  lighl  of  information  that  was  obtained 
during  the  past  year,  1909,  it  seems  altogether  probable  that  it  not 
only  occurred  but  proved  noxious  to  man,  in  Massachusetts,  as  early 
as  1830. 

The  particular  reference,  however,  to  which  attention  is  called 
may  be  found  in   the  Prairie   Farmer  for  the  year  1845,  page  216. 

"I  have  since  observed  the  male,  though  only  occasionally, 

[Clr.  118] 


Much  is  here  made  of  larvae  attacking  the  stems  of  wheal  above  the 
upper  joint,  and  in  connection  therewith  follows  this  significant  sen- 
tence: "In  one  instance  nine  eggs  were  round  in  a  single  straw,  one 
of  which  had  jusl  hatched."  Also,  in  another  journal,  we  are  (old 
tli.it  specimens  of  infested  straw  were  forwarded  to  the  Country 
Gentleman  from  Scipioville,  N.  Y.,  in  1879,  which  the  sendee  stated 
contained  eggs,  besides  larvae  and  pupa'.  In  both  cases  the  larvae 
were  almosl  beyond  a  doubt  those  of  the  greater  wheat-stem  maggot 
I  1/.  romyza  arrn  i  icana  Fitch  I.  According  to  my  0"w  n  observal  ion,  the 
mites  attack  the  larvae  of  \feromyza  americana  in  stems  of  wheat,  and 
one  can  not  fail  to  be  struck  by  the  clearness  with  which  the  state- 
ments jusl  given  describe  larvae  of  this  species  in  the  stems  of  grain 
or  grass  being  attacked  by  these  mites,  the  gravid  female  of  which 
has  oven  appearance  to  the  unaided  eve  of  being  a  minute  egg.  It 
therefore  seems  not  improbable  thai  this  mite  was  abroad  over  the 
country  at  the  earlier  date,  1845,  which  would  antedate  by  several 
years  the  description  of  the  species  in  England  by  Newport,  who 
called  attention  to  the  occurrence  of  this  mite  as  a  parasite  in  the 
nests  of  a  wild  bee  (Anthophora  retusa  L.)  in  a  paper  read  March 
5,  1850,  before  the  Linnaean  Society  of  London." 

In  the  account  given  by  Dr.  T.  \V.  Harris  in  the  second  edition 
of  his  "Insects  Injurious  to  Vegetation,"  in  connection  with  his 
discussion  of  the  early  occurrences  of  the  barley  join tworm  (Isosoma 
hordei  Harr.  .  there  are  two  very  significant  statements  that  have 
until  latel\  puzzled  the  writer  greatly.  On  page  138,  edition  of 
1852,  he  says: 

In  the  summer  of  (831,  myriads  of  these  flies  [meaning  the  adull  /  oma]were 
found  alive  in  straw  beds  in  Gloucester,  the  straw  having  been  taken  from  the  fields 
the  year  before.     An  opinion  al  thai  time  prevailed  that  the  troublesome  humors 

wherewith  man  were  then  afflicted  wer :casioned  by  the  bites  of  these 

llif-:  ami  it  is  stated  thai  the  straw  beds  of  Lexington,  being  found  to  be  infested 
with  the  same  insects,  were  generally  burnt. 

The  second  referenc -curs  on  page    l  hi  of  the  same  volume,  in 

which  it  isstated  thai  "  about  eight  years  ago  [which  would  be  aboul 
1844]  some  of  these  insects  [again  referring  to  the  barley  jointworm] 
that  had  come  from  a  straw  bed  in  Cambridge  were  shown  to  me.  'They 
had  proven  very  troublesome  to  children  sleeping  on  the  bed,  their 
bites  or  stings  being  followed  l>v  considerable  inflammation  and  irri- 
tation, which  lasted  several  days.  So  numerous  w  ere  the  insects  that 
it  was  Found  necessary  to  empty  the  bedtick  and  burn  the  straw." 

Now.  to  the  writer  it  has  always  been  puzzling  that  the  adults  of 
the  barlej  jointworm,  as  thej  were  described  1>\  Doctor  Harris, 
should   have   Keen   able   to   bite  through   bedticking  and  cause  the 


l'.     ription  published  in  Trans.  Linn.  Soc.  Lond.,  vol.  21,  p.  95,  L853. 

I  fir     lis] 


eruption  described  and  yet  not  be  able  to  gnaw  through  this  cloth 
and  make  their  escape,  as  every  one  who  has  reared  these  insects  in 
confinement  has  witnessed  their  frantic  efforts  to  escape  as  soon  as 
they  gnaw  their  way  out  of  the  straws.  The  mite  Pediculoides  ven- 
tricosus  now  furnishes  as  good  an  explanation  of  these  attacks 
referred  to  b}^  Harris  as  we  can  expect  to  secure,  after  a  lapse  of 
three-quarters  of  a  century,  with  no  possibility  of  obtaining  actual 
proof  in  the  case. 

In  1884  the  writer  found  this  same  mite  attacking  and  destroying 
the  wheat  strawworm  {Jsosoma  grande  Riley)  at  Oxford,  Inch,  and 
in  speaking  of  the  occurrence  of  this  larva  and  its  parasites,  he  made 
this  statement: 

Curiously  enough,  during  the  time  it  occupies  the  stubble  in  the  larval  and  pupal 
stage?,  it  sometimes  falls  a  victim  to  the  mite  Pediculoides  (Heteropus)  ventricosus, 
which  enters  the  stubble  from  above  after  the  grain  is  cut,  but  whose  sense  of  discrimi- 
nation is  rather  poorly  developed,  and  it  is  finally  victorious  over  the  Isosoma  larva1, 
its  parasites,  and  the  predaceous  larvae  of  Leptolrnchelus  dorsalis. 

The  same  year,  and  in  the  same  locality,  this  mite  was  again 
encountered  by  the  writer,  attacking  the  greater  wheat-stem  maggot 
in  wheat  straw,  and  the  remarkable  resemblance  of  the  gravid  fe- 
males to  minute  eggs  was  again  noted.  Since  that  time  this  Pedic- 
uloides has  been  reported  by  Mr.  E.  M.  Ehrhorn  attacking  the  larvae 
of  the  peach  twig  borer,  Anarsia  lineatella  Zell.,  in  California.0 
The  same  year  Mr.  Marlatt  reported  it  as  attacking  the  eggs  of  the 
periodical  cicada,  Tibicen  septendecim  L.6  The  same  year  Dr.  F.  H. 
Chittenden c  stated  that  this  mite  attacked  the  larvae  of  two  species 
of  bean  weevil  (Bruchus  quadrimaculatus  Fab.  and  B.  chinensis  L.) 
and  destroyed  them,  often  in  great  numbers.  Still  later,  in  1904, 
Messrs.  W.  D.  Hunter  and  W.  E.  Hinds,  in  Bulletin  No.  45,  Division 
of  Entomology,  page  107,  called  attention  to  its  attack  on  the  larvae 
of  the  cotton  boll  weevil.  In  1908  Mr.  W.  Dwight  Pierce**  stated 
that  this  mite  is  a  common  weevil  parasite  in  Mexico.  In  the 
same  publication,  page  42,  he  credited  it  with  being  parasitic,  not 
only  on  the  cotton  boll  weevil,  Anthonomus  grandis,  but  also  on  an 
allied  species,  the  pepper  weevil  (A.  eugenii  Cano).  Dr.  A.  D.  Hop- 
kins informs  the  writer  that  in  his  studies  of  forest  insects  he  has 
encountered  it  attacking  the  larvae  of  wood-boring  beetles,  and  at 
one  time,  in  West  Virginia,  it  caused  considerable  mortality  in  his 
rearing  cages,  where  he  was  attempting  to  rear  wood-boring  longi- 
corn  beetles  (Cerambyci(he)  and  barkbeetles  (ScolytidaO,  precisely 
as  experienced  by  M.Jules  Lichtenstein  in  France. 

"  Bui.  Hi,  Div.  Ent,,  U.  S.  Dept.  Agr.,  p.  17,  1898. 
'■  Bui.  I  I,  n.  s.,  Div.  Ent.,  U.  S.  Dept.  Agr..  p.  101,  1898. 
.      c  u.  S.  Dept.  Agr.,  Yearbook  for  1898,  p.  217 
<l  Bui.  73,  Bur.  Ent.,  U.  S.  Dept.  Agr.,  p.  30. 

I  fir.    lis  I 


In  the  publication  of  Messrs.  Hunter  and  Hinds  previously  re- 
ferred to,  some  information  is  given  relative  to  an  attempt  to  use 
tliis  mite  artificially  in  overcoming  the  bull  weevil.  It  has  been  ex- 
perimented with  quite  extensively  In  Prof.  A.  L.  ETerrera  and  his 
assistants  of  the  Mexican  Commission  of  Parasitology,  and  upon  his 
return  from  a  trip  to  Mexico  in  the  fall  of  L902  Mr.  Hunter  brought 
with  him,  through  the  kindness  of  Professor  Herrera,  a  supply  of  the 
parasites,  From  which  others  were  reared  for  experimental  work  in 
Texas.  This  experiment,  however,  owing  to  conditions  beyond  the 
control  of  man.  appears,  fortunately  perhaps,  not  to  have  resulted 
satisfactorily.  One  of  the  principal  obstacle-  in  this  case  seems  to 
have  been  that,  where  the  mites  succeeded  in  establishing  themselves, 
t  he\  were  subsequently  destroyed  by  the  at  tacks  of  small  ants. 

These  references  show  quite  clearly  the  wide  distribution  of  this 
mite  throughout  the  United  States  and  its  greal  variety  of  hosl 
insects.  We  have,  in  later  years,  come  to  consider  it  a  very  useful 
parasite  and  one  that  is  likely  to  attack  almost  any  soft-bodied 
larva  to  which  it  can  gain  access  and  be  secure  from  other  preda- 
ceous  insect-  and  adverse  meteorological  conditions. 

THE    MITE    PROVES    NOXIOUS    TO    MAN. 

As  indicated  in  the  earlier  portion  of  this  paper,  either  this  or 
some  other  closely  allied  species  has  long  been  known  to  occasionally 
attack  man  and  animals  in  Europe,  when  these  are  engaged  in 
handling  or  come  into  contact  with  grain  or  straw  infested  by  their 
host  insects.  The  first  instance  of  this  character  to  be  noted  in 
America,  however,  has  been  communicated  to  the  writer  by  Dr. 
Henry  Skinner,  of  Philadelphia,  Pa.  It  was  about  the  year  1896, 
while  Doctor  Skinner  was  practicing  medicine  in  Philadelphia,  that 
the  owner  of  a  boarding  house  in  one  of  the  New  Jersey  suburbs  of 
the  city  came  in  him  in  great  distress,  stating  that  the  tenant  and 
keeper  of  the  boarding  house,  which  accommodated  about  seventy- 
five  persons,  Would  not    pay  the  rent   thereon,  and   further  stated  that 

the  tenant  had  been  threatened  witli  legal  proceedings  by  the  board- 
ers, who  had  even  suggested  bodily  injury.  The  occasion  of  all  this 
trouble  was  an  epidemic  of  a  rashlike  disease,  the  causes  of  which 
were  suspected  to  reside  in  the  mattresses  of  the  beds  occupied  by  the 
patrons  of  the  house,  because  the  occupants  had  been  attacked  by 
a  \er\  mysterious  and  aggravating  -kin  eruption.  The  owner  sub- 
mitted straw  dusl  and  mattress  d6bris  taken  from  the  suspected 
beds,  and  on  examination  of  this  Doctor  Skinner  found  specimens  of 
this  mile.  The  house  was  promptly  deserted  by  the  boarders,  none 
of  whom,  a-  it  seems,  escaped  infection,  and  none  of  whom  was 
28455— Cir.  L18     10 2 


8 


The  matter  does  not  appear  to  have  been  further 


willing  to  return, 
investigated. 

In  1901  Jay  F.  Schamberg,  M.  D.,  of  Philadelphia,"  published  a  short 
paper  calling  attention  to  and  describing  "An  Epidemic  of  a  Peculiar 
and  Unfamiliar  Disease  of  the  Skin."     In  this  paper  Doctor  Scham- 
berg, who,  besides  be- 
ing a  practicing  physi- 
cian,   is    professor    of 
dermatology  and  infec- 
tious eruptive  diseases 
in     the     Philadelphia 
Polyclinic,  described  a 
number  of   cases  that 
had    been    treated    by 
him  a  few  weeks  prior 
to   the  publication   of 
his  paper.     The  erup- 
tion and  its  effect  on 
the  patient  were  briefly 
described     and     illus- 
trated, but  the  causes 
instrumental  in  bring- 
ing  about  these  attacks 
were  still   unknown  to 
him;  and,    as    several 
members  of  the  same 
household    were    com- 
monly affected,  the  dis- 
ease   was    considered 
likely  to  prove  conta- 
gious.    The    dermati- 
tis,  however,  was  not 
Ipst  sight  of,  and  in  a 
paper    contributed    to 
ill"  Public  Health  Re- 
ports Dr.  Joseph  Gold- 
berger,  passed  assistant 
surgeon  of  the  United 
States   Public  Health 
and  Marine-Hospital  Service,  in  cooperation  with  Doctor  Schamberg,6 
published  the  first  exact  information  we  have  relative  to  the  cause 
of  these  epidemics.      This  paper,  so  far  as  known  to  the  writer,  is  the 


Fio.  4.— Lesions  cau     I  b    bites  of  the  mite  PedictOoides  vcnlricoms. 
In  this  case  the  eruptions  are  excessively  large,  bli 

sparselj   p I  over  the  body  including  the  neck,  while  there  are 

none  upon  the  amis. 


[Cir.    118] 


aPhila.  Medical  Journal  for  July  6,  L901. 

6 Public  Health  Reports,  vol.  24,  No.  28,  July  9,  1909. 


first  publication  in  this  country  in  which  the  attack  of  this  mite  has 
been  followed  up  and  its  dermatologies]  effeel  on  human  beings  care- 
fully studied  and  described.  This  paper  of  Doctors  Goldberger  and 
Schamberg  maj   be  briefly  summarized  a>  follows: 

In  the  spring  and  summer  of  L 909  this  peculiar  eruptive  disease  be- 
came quite  |"v\  alent  in  Philadelphia  and  neighboring  towns.  An  out- 
break among  20  sailors  upon  a  private  yachl  docked  in  the  Delaware 
River  attracted  the  attention  of  both  thecity  and  the  federal  health 
authorities.  The  Sur- 
geon-General of  the 
United  States  Public 
Health  and  Marine- 
1  [ospital  Service  dele- 
gated Dr.  Joseph 
Goldberger,  passed  as- 
sistant surgeon,  to  pro- 
ceed to  Philadelphia 
for  the  purpose  of 
making  an  in\ estiga- 
tion  of  the  disease. 

Aiterexaininingthe 
20  sailors,  who  had 
been  senl  to  a  hos- 
pital, Doctors  Gold- 
bergerand  Schamberg 
visited  the  yacht 
w  hence  i  bey  came  and 
made  a  searching  ex- 
aniinat ion  of  the  con- 
ditions on  board. 
Their  attention  was 
directed    to    the    lad 

that  a  number  of  new- 
straw  mat t resses  had 
been  received  and  t hat 
t  lie  disease  w  as  con- 
fined to  those  who  had  slept  upon  these  mattresses  or  had  placed  their 
clothes  n  |  ion  t  hem.  Eleven  officers  and  members  of  the  crew  who  did 
not  sleep  upon  t  he  new  mattresses  remained  entirely  free  of  the  disease. 
At  about  the  same  period  information  was  received  concerning  an 
eruptive  disease  prevailing  among  the  sailors  of  four  other  boats, 
plying  along  the  Delaware  River.  Investigation  disclosed  the  fact 
thai  these  boats  had  also  received  new  straw  mattresses,  and,  further- 
more, that  onl\  those  were  attacked  who  slepl  upon  the  mattresses 
or  Otherwise  came  in  contact  with  them. 
[Cir.  us) 


Fig.  5.— Lesions  cau  of  the  mite  Pedicuioidi 

In  this  case  the  eruptions  are  almost  the  reverse  of  those  shown  in 
■  much  smaller,  mon  placed,  and  confined 

more  to  the  lower  portion  of  I  ere  still  being  very  few  on 

either  neck  or  arms. 


10 


111  addition  to  these  cases  among  sailors,  Doctors  Goldberger  and 
Schamberg  examined  or  received  authentic  information  concerning 
seventy  other  cases  of  this  disease  occurring  in  twenty  different 
households  in  Philadelphia  and  its  vicinity. 

In  practically  every  instance  they  were  enabled  to  determine  that 
the  patient  had  either  recently  slept  upon  a  new  straw  mattress  or 
had  freely  handled  the  same.  Where  only  one  person  in  a  household 
was  affected,  it  was  found  that  he  was  the  only  one  to  occupy  a  bed 
supplied  with  a  new  straw  mattress.     They  were  able  to  trace  all  of 

the  incriminated  mat- 
t  resses  to  four  leading 
mattress  manufactur- 
ers. Figures  4,  5,  6, 
and  7,  from  photo- 
graphs by  Doctor 
Schamberg,  show  the 
condition  of  some  of 
the  victims  and  illus- 
trate different  forms 
of  the  eruption. 

Careful  investiga- 
tion warranted  them 
inexchuling  from  con- 
sideration the  ticking 
of  the  mattresses  and 
the  jute  or  cotton  top- 
ping contained  there- 
in. The  cause  of  the 
disease  was,  therefore, 
circumscribed  to  the 
si ia\v.  Repeated  in- 
quiries elicited  the  in- 

Fig.  6.— Lesions  caused  bj  b       of  thi  mite  Pedit  Ho  '  usus.  formal  ion    that    all   of 

In  this  figure  the  eruptions  are  still  more  minute,  covering  the  a  |.  (%        m 'in llf-iel  lirers 
entire  body,  including  the  arms  and  neck,  the  hair  having  been  _ 

removed  from  the  neck  to  show  their  diffusion  even  on  the  base  of  had    received,    at    the 

the  head.    The  lesions  are  also  less  swollen  than  shown  in  figure  5.  i  •      „    j  1  .   <]  jc<vwp-r>ro- 

ducing  mattresses  were  made  up,  wheat  straw  from  a  dealer  in 
Salem  County,  in  soul  hern  New  Jersey.  One  manufacturer  had 
used  straw  from  this  source'  exclusively  in  the  affected  mattresses, 
while  in  another  case  the  straw  had  come  from  southern  Indiana. 

Finding  of  a  parasite.  Doctors  Goldberger  and  Schamberg  sifted 
the  straw  from  a  mattress  through  the  meshes  of  a  fine  flour  sieve 
upon  a  large  piece  of  plate  glass  covered  with  white  paper,  (lose 
scrutiny  of  the  siftings  under  strong  electric  illumination  soon  de- 
tected some  slight  motion.  The  moving  particles  were  touched  with 
[Cir.   UN] 


11 


a  needle  moistened  in  glycerine  and  transferred  to  a  glass  slide. 
Search  with  the  microscope  disclosed  the  presence  of  a  mite  of  very 
minute  dimensions.  The  mite  was  identified  for  them  by  Mr.  Nathan 
Banks,  expert  in  A.carina  of  the  Bureau  of  Entomology,  United  Slates 
Department  of  Agriculture,  as  very  close  to,  if  uol  identical  with, 
the  P<  diculoidi  s  <■<  ntricosus. 

In  order  to  demonstrate  experimentally  the  etiological  relation- 
ship of  the  suspected  straw  mattresses,  Doctor  Goldberger  exposed 
his  bared  lefl  arm  and  shoulder  for  one  hour  between  two  mattresses. 
At  the  end  of  about 
sixteen  hours,  a  num- 
ber of  characteristic 
lesions  appeared  upon 
the  arm,  shoulder,  and 
chest;  Later,  three 
volunteers  slept  upon 
the  mattresses  and 
each  one  developed 
the  eruption  at  the 
end  of  about  the  same 

period. 

I  )octor  ( roldberger 

later  touk  some  of  the 
sifted  si  raw,  di\  ided 
it  into  two  portions, 
and    placed    il    in  t  wo 

c  1  ea  n  Pel  ri  glass 
dishes.  One  of  t  bese 
was  applied  for  one 
hour  to  t  he  left  axilla 
of  a  volunteer.  At  i  be 
end  of  From  sixteen  to 
seventeen  hours  the 
charact  erist  ic  erup- 
tion was  present  in 
the    area    of    the    left 

axilla  to  which  the  Petri  dish  of  straw  siftings  had  been  applied. 
The  second  portion  of  the  st  raw  siftings  in  a  Petri  dish  was  exposed 
to  the  vapor  of  chloroform  under  a  bell  jar  with  a  view  to  killing  any 
insect  or  acarine  thai  might  be  present.  These  siftings  were  then 
applied  to  the  right  axilla  of  the  same  volunteer  to  whose  left  axilla 
t lie  untreated  siftings  had  Keen  applied.  The  chloroform  evidently 
destroyed  in  the  siftings  the  agent  that  was  producing  the  eruption, 
for  do  lesions  appeared  alter  the  application  of  the  chloroformized 
-hi  ings. 

[Clr.   118] 


Fig.  7.-  i  i       '  '1  by  bites  of  the  mite  I 

In  this  case  the  effect  is  entirely  diffei  io\vn  in  any  of 

■  ■  i  \ .  including 
the  arms,  but  extending  over  the  face  and  (orehi 

ilar,  inflamed 
patches.    This  figure  Illustrates  the  liability  of  tl 
mistaken  for  other  mallpox  and 

spotted  fi\ er. 


12 


Doctor  Goldberger,  further,  removed  from  some  straw  siftings  five 
minute  mites,  and,  placing  them  in  a  clean  watch  crystal,  applied  the 
crystal  to  the  axilla  of  another  volu  nt  eer.  At  the  end  of  about  sixteen 
hours  following  this  application  five  of  the  characteristic  lesions  ap- 
peared on  the  area  to  which  the  mites  had  been  applied.  (See  fig. 
8,  from  drawing  by  F.  H.  Wilder.) 

INFLUENCES    CONTROLLING    THE    EXCESSIVE    ABUNDANCE    OF 
PEDICULOIDES. 

It  will  be  noticed  that  Doctors  Goldberger  and  Schamberg  made  no 
attempt  to  discover  the  underlying  causes  for  the  enormous  numbers 
of  these  mites  inhabiting  the  mattresses  involved  in  their  investiga- 
tions, that  problem 
coming  properly 
within  the  realm  of 
entomology.  When 
the  writer  took  up 
this  subject  with  the 
view  of  finding  out 
the  causes  for  such  an 
abundance  of  these 
mites,  Doctors  Gold- 
berger and  Schamberg 
very  kindly  placed  at 
his  disposal  every- 
thing in  their  posses- 
sion relating  to  this 
epidemic,  including 
the  mattress  which 
Doctor  Goldberger 
had  himself  used  in 
experiments  with  this 
mite,  carried  out  by 
him  at  the  Hygienic  Laboratory  in  Washington.  Doctor  Schamberg 
was  equally  kind  in  placing  at  his  service  all  of  the  material,  notes, 
and  photographs  in  bis  possession. 

Almost  at  the  commencement  of  the  investigation,  Dr.  William 
Royal  Stokes,  of  the  Maryland  state  board  of  health,  informed  the 
writer  that  a  similar  but  less  extensive  epidemic  had  shortly  before 
been  noted  in  Baltimore.     This  he  kindly  described  as  follows: 

The  matter  was  brought  to  my  attention  by  several  persons,  who  came  to  the  head 
of  the  department  and  complained  of  the  skin  eruption  described.  They  stated 
that,  a  number  of  people  in  a  suburban  hotel  were  similarly  affected,  but  I  do  not 
remember  the  number  at  ibis  late  date.  These  persons  volunteered  the  information 
that  they  had  all  been  sleeping  on  some  new  Btraw  mattresses,  and  that  all  of  the 
pei  ons  similarly  affected  had  used  these  mattresses. 
[CIr.  118] 


t 

w 

■*- 

W* 

.  8.— Lesions  caused  by  bites  of  the  mite  PedictUoides  vintricosus. 
\iiout  natural  size. 


13 

I  .-aw  Doctor  Gilchrist,  ili>>  clinical  professor  of  dermatology  al  Johns  Hopkins 
University,  yesterday,  and  he  gave  me  the  following  description  of  th 
which  he  Baw  al  the  health  department,     f  saw  two  other  cases  which  corresponded 
w  ith  these  in  a  general  way. 

"The  eruption  consisted  of  about   1,000  wheals,  or  erythemato-withicarial  sp 
papulo-withicarial  lesions.     As  in  the  description  in  the  reprint  of  Doctors  <  roldberger 
and  Schamberg,  of  the  United  States  Public  Health  and  Marine-Hospital  Service, 
they  varied  in  size  trom  a  lentil  seed  to  a  finger  nail,  and  arc  round,  oval,  orirregular 
in  Bhape.     No  vesicles  or  pustules  were  seen.     The  eruption  was  on  the  neck,  chest, 

abdomen,  and  hack,  and  al.- i  arms  and  legs.     Itching  was  present,  and  all  lesions 

showed  evidences  of  scratching." 

Besides  this,  there  were  several  cases  reported  to  the  writer  from 
northern  Maryland,  where  farmers  in  running  their  wheal  through  a 
fanning  mill  had  been  simultaneously  troubled  by  a  very  similar  or 
identical  erupl  ive  disease  of  the  skin.  In  another  instance,  a  th  rasher- 
man  engaged  in  feeding  the  unthrashed  grain  into  the  cylinder  of 


jg 

—^ 

t 

Ml  > 

"^jS 

l>     \ 

t\ 

1 

Wm 

V 

/                  1 

f              \ 

J 

FlG.9. — Aiiuii  oliointv/onn (lsosomalritici).    Much  enlarged.   (From  Howard.) 

the  thrashing  machine  was  also  affected  by  a  disease  of  the  skin,  en- 
tirely unfamiliar  to  the  attending  physician,  who  could  not  classify 
it  with  any  urticaroid  dermatitis  known  to  him.  After  the  writer's 
experience  of  previous  year-,  it  seemed  impossible  thai  this  Pedicu- 
loides  should  become  sufficiently  abundant  to  cause  this  dermatitis 
without  there  being  an  excessive  abundance  of  some  bos!  inseel  or 
insects  affecting  either  the  straw  or  the  grain  itself.  Naturally,  the 
studies  made  by  him  in  1882  led  him  to  suspect  that  the  Ajigoumois 
grain  moth  (Sitotroga  cerealeUa)  might  he  responsible  for  the  abund- 
ance of  the  mites.  Then,  too,  the  fact  that  it  attacked  the  wheat- 
straw  worm  (foosoma  grand*  Rilej  I  in  wheat  straw  led  him  to  suspect 
that,  as  this  particular  species  i-  not  known  to  occur  in  the  vicinity 
id'  Philadelphia,  while  it--  near  relative,  the  joint  worm  (Isosoma 
ti'iin'i  Fitch)  (fig.  9),  does  occur  more  or  less  abundantly  over  the 

[Clr,   l  ts| 


14 

eastern  part  of  the  country,  this  latter  species,  too,  might  perhaps  be 
involved. 

With  a  view  to  finding  out  something  of  the  abundance  of  the  grain 
moth  in  New  Jersey,  from  which  State  was  obtained  most  but  not 
all  of  the  straw  entering  into  the  mattresses  mentioned  by  Doctors 
Goldberger  and  Schamberg,  the  writer  applied  to  Dr.  John  B.  Smith, 
state  entomologist,  for  information.  In  reply  Doctor  Smith  was 
kind  enough  to  send  the  writer  an  advance  copy  of  the  report  of  his 
department  of  the  New  Jersey  Agricultural  Experiment  Station  for 
the  year  1908,  and  from  this  publication  it  was  learned  that  during 
the  summer  of  that  year,  owing  to  favorable  weather  conditions,  this 
moth  developed  rapidly  in  the  field  and  there  was  great  damage  to 
wheat  among  those  farmers  who  delayed  thrashing  until  September 
or  later.  Furthermore,  a  very  large  percentage  of  the  wheat  crop 
gathered  that  year  became  useless  for  milling  purposes,  and  so  general 
was  the  infestation  that  grain  from  some  localities  was  entirely 
barred  at  mills  except  when  ground  for  the  owner.  Some  further 
investigations  carried  on  in  eastern  Pennsylvania  revealed  a  very 
similar  condition  of  affairs.  It  was  the  straw  of  1908,  coming  mostly 
from  New  Jersey,  but  a  small  part  of  it  from  Indiana,  that  entered 
into  the  mattresses,  from  the  use  of  which  came  the  epidemic  in  and 
about  Philadelphia. 

In  order  to  settle  these  points,  Mr.  V.  L.  Wildermuth,  of  the  Bureau 
of  Entomology,  was  instructed  to  examine  the  straw  in  the  mattress 
placed  at  the  writer's  disposal  by  Doctor  Goldberger.  After  a  day 
and  a  half  of  careful  search,  only  five  straws  affected  by  the  joint- 
worm  were  found.  This  seemed  to  entirely  eliminate  this  species 
from  consideration  in  connection  with  this  particular  epidemic. 
There  were,  however,  many  wheat  heads  remaining  attached  to  the 
straw,  and  these  heads  contained  a  great  many  kernels,  the  contents 
of  which  had  been,  eaten  out  by  the  larva1  of  the  grain  moth.  More- 
over, these  eaten  kernels  contained  great  numbers  of  the  dead  bodies 
of  Pediculoides.  That  the  Angoumois  grain  moth  was  the  cause  of 
this  damage  to  the  wheat  was  still  further  proved  by  the  emergence 
of  an  adult-  moth  from  these  eaten  kernels  on  November  15.  The 
larva?  of  this  moth  infested  the  kernels  of  wheat  before  the  latter  were 
thrashed.  Many  of  these  infested  kernels  remaining  in  the  straw 
were  included  in  the  materia]  going  into  the  manufacture  of  these 
mattresses.  The  greater  portion  of  the  living  larva'  of  the  moth 
would  develop  to  adults  during  May  or  early  June,  thus  cutting  off 
the  food  supply  of  these  mites.  The  mites  would  therefore  very 
naturally  swarm  among  the  straw  and,  making  their  way  through 
the  cloth  covering  of  these  mattresses,  attack  anything  that  gave 
promise  of  furnishing  food  and  preserving  them  from  starvation.  It 
seems  that  starvation  is  the  filial  outcome,  however,  for,  as  already 

[Cir.   118] 


15 


stated,  no  trouble  is  experienced  in  using  the  mattresses  after  a  cer- 
tain period,  which  period  probablj  indicates  the  termination  of  the 
life  of  the  miles  infesting  the  straw.  It  therefore  did  nol  seem  nec- 
essary to  seek  further  for  the  primary  cause  of  this  eastern  epidemic 
of  dermatitis,  the  center  of  which  seems  to  have  been  in  and  about 
Philadelphia. 

A    WESTERN     EPIDEMU     Ol     THE    DERMATITIS. 

"While  the  problem  of  the  epidemic  in  the  East  was  apparently 
solved,  some  of  the  wheat  straw  involved  therein  had  come  from 
Indiana,  and  during  the  last  few  years  an  outbreak  of  the  jointworm 
(figs.  !o  ami  11)  had  been  gathering  force  throughout  Ohio,  Indiana, 
and  soul  hern  Illinois, 
until  during  the  sum- 
mer of  1 908  \ ei\  seri- 
ous damages  occur- 
red .  [nvesl  igation 
of  the  insect  during 
previous  years  had 
shown  that  the  out- 
break really  began 
in  the  more  ele"\  ated 
portions  of  Virginia, 
in  the  upper  Shenan- 
doah Valley,  in  West 
Virginia,  and  in  east- 
ern <  )iiio,  ;is  curly  as 
190  1,  afterwards  ad- 
vancing broadly  to 
the  west w ard. 

During  the  sum- 
mer of  L908  there 
came  to  the  Bureau  of  Entomology  from  this  section  of  the 
country  a  greal  nutnber  of  complaints  of  serious  skin  trouble 
among  people  engaged  in  thrashing  grain  that  had  been  stored 
for  some  time  in  barns,  and  in  some  localities  it  had  become 
difficult  to  secure  help  to  thrash  under  such  conditions.     Also  the 

sai lisorder  was  encountered   by  those  who  used  this  straw  for 

the  purpose  of  filling  bedticks,  or  as  ,-i  substitute  for  felting  under 
carpets,  and  in  one  case  berry  pickers  had  been  attacked  when  such 
straw  had  been  used  as  a  mulch  for  berry  |>lani^.  This  straw  came 
from  a.  held  that  had  been  seriously  damaged  from  jointworm  attack 
in  1908.  In  one  instance  a  carload  of  wheat  straw  was  shipped  to 
Pittsburg,  Pa.,  and  six  men  engaged  in  unloading  it  were  attacked 

i  18] 


i        10     Effect  of  jointwi.i    i  traw  in  Held.    Note 

enlargements  and  distortions.    Reduced.    (Original.) 


16 


by  some  skin  eruption,  and  the  horses  used  in  hauling  this  straw  after 
it  was  unloaded  also  suffered  from  what  was  seemingly  the  same 
disorder.  Perhaps  the  following  from  a  correspondent  of  the  Bureau 
of  Entomology,  residing  in,  southern  Ohio,  will  give  a  fair  idea  of  the 
situation  on  man}'  farms  in  that  section  of  the  country: 

About  four  years  ago  a  parasite  was  found  when  thrashing  wheat  out  of  barns.     It 
seemed  to  affect  the  victims  almost  as  soon  as  they  got  into  the  mow.    The  men  began  to 

scratch  themselves,  generally  on  the 
neck  and  on  the  arms  (inside)  opposite 
the  elbow,  and  on  the  body  back  and 
front.  The  parasites  raised  welts  such 
as  you  describe  and  spread  as  you  in- 
dicate They  have  spread  to  such  an 
extent  that  farm  hands  dread  them 
and  will  not  change  work  with  neigh- 
bors unless  they  thrash  in  the  field. 
Hereof  Late  they  are  found  in  wheat 
straw  in  the  barns,  especially  if  baled. 
Last  week  a  farmer  brought  me  baled 
wheat  straw  that  seemed  to  be  alive 
with  them.  They  attacked  every  one 
that  went  into  1  he  barn,  and  one  of  my 
horses  that  was  perspiring  from  effects 
of  a  drive  was  simply  covered  with 
little  knots  or  swollen  places  and  bit 
and  rubbed  himself  continually.  I 
had  to  have  the  straw  hauled  out  and 
burned  and  the  barn  disinfected.  The 
farmer  stated  thai  they  were  so  thick  in 
the  shed  thai  contained  the  si  raw  that 
he  had  in  keep  all  stuck  out  of  the  shed. 

.Many  other  similar  Letters 
from  towns  in  Ohio  were  re- 
ceived by  Doctor  Schamberg, 
particularly  from  Zanesville, 
Columbus,  Vincent,  Springfield, 
etc.,  where  the  affection  is 
popularly  believed  to  he  due  to 
"doggers."  A  physician  from 
the  last-named  town  stated  that 
in  the  fall  of  1908  during  harvest  and  thrashing  time  he  saw  in  Wash- 
ington County  some  87  eases  of  the  disease  iii  question.  It  affected 
the  harvesters  and  thrashers.  This  spring  he  observed  38  cases  from 
contact  with  straw  ticks  refilled  with  straw  of  last  fall's  crop.  The 
disease  is  said  to  have  heen  more  prevalent  last  year  (1908)  than  ever 
before.  Information  has  come  from  Columbus,  Ohio,  that  potters 
who  used  straw  for  packing  crockery  ware  have  heen  so  badly  attacked 
at  times  that  the  entire  force  of  packers  has  heen  off  duty.  Many 
rcir.   L18] 


Fi(i.  11.— Female  Isosoma  in  act  of  depositing  ojtk  in 
stem.    About  life  size.    (Author's  illustration.) 


17 

times  a  whole  carload  of  straw  bias  Kith  30  affected  thai  the  use  of 
it  has  been  abandoned.  In  Springfield,  Ohio,  it  is  said  thai  the  dis- 
ease was  so  bad  a  year  or  two  ago  in  the  lowlands  west  of  the  city  as 
seriouslj  to  tamper  the  progress  of  the  construction  of  a  large  sewer; 
this,  however,  blight  have  been  due  to  attack  by  other  mites.  In 
Zanesville,  Ohio,  the  potters  have  Keen  obliged  to  abandon  the  use 
of  Btraw  and  emplo}  "prairie  hay"  for  packing  purposes. 

Doctor  Schamberg  was  also  informed  by  a  physician  of  Pittsburg 
that  a  young  woman  patient  had  suffered  from  an  affection  closelj 
resembling  if  nut  identical  with  the  one  under  consideration  each 
time  that  she  had  assisted  in  emptying  cases  of  dishes  packed  in 
straw.  Both  the  physician  and  the  patient  had  come  to  believe  that 
something  in  the  straw  was  the  cause  of  the  eruption. 

Indeed,  so  nearly  did  the  territory  from  which  these  complaints 
came  to  us  coincide  with  that  affected  by  the  jointworm  that  it 
created  the  suspicion,  not  only  among  those  engaged  in  the  invent  iura- 
tions,  hut  even  among  farmers  themselves,  that  there  must  he  some 
connection  between  the  two  phenomena.  Very  many  of  these  cases 
were  brought  to  tlu>  notice  of  practicing  physicians,  hut  the  latter 
were  at  a  loss  to  account  for  the  prevalence  of  this  dermatitis,  nian\ 
of  them  supposing  it  to  be  some  species  of  rash  that  was  more  or  less 
contagious,  the  exact  nature  of  which  t  he\  did  not  know.  The  lia- 
bility of  confusion  with  other  vastly  more  serious  contagious  diseases, 
notably  smallpox,  was  of  course  veiy  great. 

Among  these  physicians  was  Dr.  Lyman  T.  Rawles,  of  Hunter- 
town,  Ind..  who,  in  May,  1909,  undertook  a  careful  study  of  a  number 
of  cases  of  this  dermatitis  that  had  come  tinder  hi-  personal  observa- 
tion, as  well  as  those  of  some  of  bis  associates.  Doctor  Rawles's  inves- 
tigations were  very  carefully  made,  and  the  results  are  exceedingly 
valuable  for  the  reason  that,  in  the  case  of  this  western  epidemic,  he 
was  able  to  trace  the  cause  i>\'  the  skin  eruption  to  the  mite  (Pedicu- 
loides  ventricosus)  and  follow  this  back  to  the  host  insect,  the  wheat 
jointworm  {Isosoma  tritici)."  It  clear-  up  the  obscurity  surrounding 
the  cause  of  this  epidemic  in  the  Middle  West,  a  section  throughout 
which  the  Angoumois  grain  moth  never  occurs  in  excessive  abundance 
excepting  in  grain  that  is  kept  in  store,  and  then  only  in  the  more 
southern  portion  of  Indiana  ami  Illinois. 

In  May,  1909,  Doctor  Rawles  found  in  his  practice  that  a  very 
strikingly  strange  skin  disease  presented   it-elf  in  his  own  and   the 

"( )w  -iii-  to  an  unfortunate  misunderstanding,  for  which  do  one  connected  with  these 
investigations  is  responsible,  I1  tor  B  vies  did  do!  receive  a  proper  determination 
of  the  mite  involved  in  liis  studies  of  the  dermatitis.  The  entomological  nomencla- 
ture in  bis  paper,  printed  in  the  Journal  of  the  Indiana  Stale  Medical  Association, 
August,  L909,  should  therefore  !"■  corrected  by  substituting  PedicuL 
for  Ditropinotus  aurem  iridii  wherever  the  latter  oameoccure  F.  M.  \Y. 
[Clr.   ns| 


18 

surrounding  country  in  epidemic  form.  Through  the  press  notes  ii 
seemed  to  be  quite  general  over  the  northern  part  of  the  United 
States,  limiting  itself  to  the  wheat-growing  sections. 

The  people  generally  affected  were  farmers  and  those  Irving  in 
small  villages  or  towns  where  straw  is  used  in  beds,  under  carpets,  and 
around  stables  to  bed  stock.  Horses  and  cattle  have  been  seen  with 
a  skin  disease  almost  identical  with  that  seen  in  man.  The  following 
incident  led  him  to  an  investigation  as  to  the  probable  etiology: 

A  family  had  cleaned  house,  refilled  the  straw  ticks  of  their  beds, 
and  placed  fresh  straw  under  the  carpets,  and  in  about  one  week  the 
family  had  developed  this  peculiar  skin  disease.  In  the  beds  was 
found  a  small  black  fly  (Isosoma  tritici  Fitch)  about  the  size  of  an 
ordinary  gnat,  which  at  first  it  appeared  to  be,  but  closer  observation 
revealed  that  it  was  not  of  the  gnat  family.  Upon  examination  of  the 
straw  it  was  found  that  a  large  number  of  the  straws  were  perforated; 
these  perforations  were  through  the  wall  in  the  region  of  the  joint, 
generally  about  2  inches  from  the  joint.  The  perforations  were  about 
the  size  of  a  small  pinhole  and  ranging  in  number  from  ten  to  thirty  in 
a  straw.  Upon  examining  a  section  of  this  straw  the  small  black  fly 
was  found  under  many  of  the  openings  through  the  walls. 

Several  flies  were  examined  to  ascertain  if  they  possessed  a  piercing 
proboscis,  and  while  observing  one  which  had  just  been  taken  from 
under  the  sheath  of  the  straw,  through  which  then1  was  no  perforation 
over  the  fly,  a  small  mite  was  observed  crawling  over  the  dead  body 
of  the  fly. 

Placing  the  bodies  of  several  of  these  flies  under  the  microscope  and 
using  a  one-fourth-inch  objective  and  a  No.  5  eyepiece,  it  was  found 
that  on  nearly  all  flies  over  which  the  wall  was  intact  a  small  mite 
could  be  detected,  these  varying  in  number  from  two  to  four  mites  to 
each  fly.  Upon  furthering  the  observations  it  was  found  that  the 
dermatitis  lasted  after  the  flies  had  been  observed  and  exterminated. 

The  following  experiments  were  tried  to  prove  whether  it  was  the 
fly  or  the  mite  that  was  the  etiologic  factor  in  producing  the  dermatitis. 

Six  live  Hies  were  taken,  upon  which  no  mites  could  be  found; 
these  were  placed  under  a  watch  glass  and  bound  upon  the  right  arm, 
leaving  them  in  contact  with  the  skin  for  three  hours.  Upon  the  left 
arm  four  dead  Hies,  on  which  living  mites  had  been  observed,  were 
placed  under  a  watch  glass  and  left  in  contact  with  the  skin  for  three 
hours,  after  which  the  glasses  were  removed  and  resulls  awaited. 
The  right  arm  showed  nothing.  Upon  the  left  arm  there  appeared 
within  twelve  hours  four  small  wheals,  the  character  and  evolution  of 
which  are  later  described. 

To  further  the  experiments  some   fresh    lesions   of   patients   were 
scraped  and  the  scrapings  examined  microscopically,  and  two  of  the 
mites  were  found  in  the  scrapings. 
[Cir.  118] 


19 

[tching  is  the  most  prevalent  and  nrsl  symptom  to  attracl  the 
at  tout  ion  of  the  patient.  It  is  most  persistent  and  intense  during 
the  after  part  of  the  aight.  At  aboul  the  time  the  itching  was  most 
intense  there  appeared  an  urticarial  eruption,  accompanied,  in  severe 
cases,  with  genera]  systemic  symptoms,  such  as  rise  of  temperature 
from  99  to  102;  in  one  case  the  temperature  rose  to  103.8;  the  pulse 
rate  is  accelerated  to  LOO,  or  as  high  as  110— in  one  case  to  L30. 
Other  symptoms  were  intense  headache,  anorexia,  nausea,  in  sunn' 
cases  vomiting,  and  a  mild  form  of  diarrhea.  In  severe  cases  some 
complained  of  general  joint  pains  and  backache ;  in  t  hese  cases  t  he  urine 
was  examined  and  albumin  in  small  amount  was  found,  but  no  casts  or 
blood.     When  the  acute  symptoms  disappeared,  so  did  the  albumin. 

Many  patients  who  suffered  from  mild  cases  complained  of  nothing 
aside  from  th<  intense  itching.  If  all  straw  was  removed  from  the 
beds  and  house,  t  lie  symptoms  would  subside  in  one  or  two  days  and 
completely  disappear  in  a  few  days  more. 

The  lesion,  which  is  typical  of  the  disease,  is  the  urt  icaria  vesiculosa. 
The  urt  icaria  1  Lesion  varies  in  size  from  thai  of  a  split  pea  to  that  of  a 
penn\  :  it  is  surrounded  by  a  pinkish  halo,  varying  in  intensity  of 
color  from  a  pale  pink  to  a  most  brighl  pink.  The  "hive"-like 
lesion  is  at  first  blanched,  hut  later  becomes  a  rose-red  color.  It  is 
elevated  aboul  1  or  2  millimeters  above  the  skin  surface,  and  is  sur- 
mounted by  a  small  vesicle  containing  a  whitish  lluid  marking  the 
I  dace  of  i  noc  u  hit  ion.  The  vesicle  is  aboul  I  or  2  millimeters  in  diame 
ter  and  (derated  about  •">  millimeters  above  the  surface  of  the  urti- 
carial lesion.  As  the  lesion  grows  old  it  goes  through  the  process  of 
evolution:  (1)  It  is  blanched  and  has  a  central  vesicle;  (2)  it  is  rose- 
red  and  the  vesicle  may  become  a  pustule;  (3)  it  generally  recedes  to 
the  skin  level  with  scab  formation,  due  to  the  scratching ;  I  1 1  it  leaves 
a  brow  nidi  or  greenish-yellow  or  purple  spot  on  the  skin  surface.  In 
debilitated  patients  the  markings  look  not  unlike  faded  indelible- 
pencil  marks.  (This  was  noted  in  a  patient  suffering  from  pulmonary 
tuberculosis.)     These  discolorations  may  lasl  for  several  weeks. 

The  anatomical  location  of  the  lesions  is  generally  the  hack,  -ides, 
and  abdomen,  and  less  frequently  the  arms  and  legs.  Tin-  neck  has 
very  few  lesions;  the  lace,  hands,  and  feet  have  very  few  or  none. 

The  number  of  lesions  depends  upon  the  number  of  mites,  ranging 
from  very  few  to  thousands;  in  some  cases  the  hack  and  abdomen 
have  been  almost  a  solid  mass  of  lesions  new  lesions  on  the  tops  of 
old  Lesions,  so  having  Lesions  in  all  stages  of  development. 

Later  investigations  carried  out  by  Mr.  Wildermuth,  at  Lafayette, 
Ind.,  during  December,  L909,  and  January  and  February,  L910,  show 
that  where  straw  is  kept  in  masses,  as  in  stacks  and  barns,  the  mites 
literally  swarm  through  the  straw,  and  as  -nun  as  an  tsosoma  or  its 
parasites  attempt    to  gnaw    their  waj    out   through  the  cells  in  the 

[Clr.   us] 


20 

straw,  the  mites  enter  and  kill  them  before  they  are  able  to  enlarge 
the  opening  sufficiently  to  enable  them  to  make  their  escape;  indeed, 
not  more  than  5  per  cent  succeeded  in  escaping. 

As  this  represents  fairly  well  the  conditions  of  straw  in  spring  and  early 
summer  when  it  is  used  for  the  manufacture  of  mattresses  and  on  the 
farms  for  the  filling  of  straw  ticks  and  as  a  substitute  for  felting  under 
carpets,  the  great  number  of  cases  of  this  dermatitis  occurring  over  the 
country  is  not  at  all  surprising,  and  the  indications  for  the  season 
of  1910  are  more  favorable  for  an  increase  than  a  decrease  in  the  trouble. 

OBSCURITY    SURROUNDING    THE    OCCURRENCE    OF    THIS    SKIN    DISEASE. 

The  exact  nature  of  this  eruptive  disease  was  not  at  all  understood 
by  the  medical  profession  throughout  the  country.  In  southwestern 
Virginia  thrashermen  suffered  from  the  same  disorder,  but  attributed 
it  to  "chiggers"  (fig.  12),  and  local  physicians,  though  skeptical,  were 
themselves  unable  to  correctly  diagnose  or  to  account  for  the  trou- 
ble.    As  the  disease  is  not  serious  and  passes  away  in  the  course 

of  time  without  leaving 
the  patient  in  any  way 
permanently  injured, 
it  seems  to  have  been 
passed  over  by  medical 
men  without  investiga- 
tion, excepting  by  the 
physicians  whose  publi- 
cations have  just  been 
cited.  Among  the  peo- 
ple themselves  the  erup- 
Fig.12.  Leptusamericanus&tlelt;  Leptusirritans  at  right.  Highly  tion  wis  nrob'lblv  more 
magnified.    (After  Riley.)  ' 

frequently  attributed  to 
attacks  of  "chiggers"  or  a  "rash  "than  to  any  other  cause,  and  it  is  quite 
likely  that  this  common  erroneous  interpretation  of  the  origin  of  the 
eruption  has  prevailed  generally  throughout  the  country,  including  the 
upper  Shenandoah  Valley  in  Virginia,  where  the  jointworm  was  abun- 
dant as  far  hack  as  1904.  It  was,  consequently, rather  unfortunate 
that,  with  the  beginning  of  this  disorder,  an  institution  in  one  of  the 
States  involved  should  publish  a  newspaper  bulletin  crediting  the  epi- 
demics of  t  his  eruption  to  the  attack  of  "chiggers,"  and,  furl  hermore. 
that  a  second  press  bulletin,  accentuating  the  first,  should  have  been 
issued  and  sent  to  every  newspaper  in  the  State  and  from  these  copied 
into  other  newspapers  throughoul  the  country.  Tims  it  was  that  an 
entirely  erroneous  impression  was  magnified  and  still  further  diffused. 
In  older  to  determine  the  likelihood  that  those  handling  straw  in 
the  wheal  field  will  he  attacked  by  the  small  red  mites  often  mistaken 
for  "chiggers"   that   abound  in  the  harvested  grain  at  this  time, 

[Cir.   118] 


2] 

Mr.  Wildermuth,  oi  the  Bureau  of  Entomology,  made  a  number  of 
experiments.  Tn  no  case  was  he  able  to  provoke  an  attack  from 
these  red  mites,  probablj  Tydeus  sp.,  even  when  the}  were  confined 
upon  the  skin  of  his  bare  arm.  On  the  other  hand,  examinations  of 
straw  from  various  points  in  Ohio  and  Indiana  have  revealed  the 
presenc  of  Pediculoides  in  the  cells  occupied  by  the  jointworm. 
This  seems  to  entirety  eliminate  "  chiggers"  from  these  investigations 
because  these  were  probablj  nol  presenl  and  there  does  not  longer 
appear  to  l>e  any  doubl  thai  Pediculoides  ventricosus  is  to  be  charged 
with  causing  the  epidemic  of  this  dermatitis.  The  cause  of  its  nun 
excessive  abundance  lies  in  the  outbreaks  of  the  Angoumois  grain 
moth  upon  the  grain  in  the  East  and  the  jointworm  in  the  wheal  stra^ 
in  the  Middle  West.  Therefore  "chiggers"  do  not  appear  to  figure  as 
a  cause  in  such  epidemics. 

LIGHT   THROWN    UPON    OTHER    PROBLEMS. 

These  investigations  have  illustrated  very  nicelj  the  extent  to 
which  the  solution  <>t'  one  entomological  problem  will  at  the  same 
time  also  solve  other  problems  more  or  less  closel}  allied  to  the  orig- 
inal one.  The  light  thrown  upon  the  cases  of  eruption  noted  by 
Doctor  Harris  in  connection  with  the  barley  jointworm  has  already 
been  explained.  The  present  outbreak  of  the  jointworm  in  the  Ohio 
Valley  probably  originated  in  the  upper  Shenandoah  Yalle\  of  Vir- 
ginia, extending  northward  and  westward  throughout  West  Virginia 
and  eastern  Ohio.  When  investigation  of  the  insect  was  taken  up  in 
I '.hi  i  ;,  parasite,  Ditro'pinotus  aureoviridis Crawford,  was  also  noted  in 
excessive  abundance,  hut  for  some  reason  it  did  not  overcome  the  joint- 
worm.  This  phenomenon  has  been  noted  continually.  Since  that 
time  it  has  been  a  perpetual  enigma  to  the  writer  why  it  was  that  with 
such  an  abundance  of  its  natural  enemies  the  jointworm  should  con- 
tinue to  spread  and  increase  in  dest  ruct  iveness.  Now,  however,  that 
we  know  t  hat  this  predaceous  mite  is  able  to  develop  through  a  series  of 
years  in  such  immense  numbers  in  connection  with  the  jointworm,  the 
matter  comes  nearer  a  solution.  Ditropinotus,  a-  well  as  some  other 
parasitic  enemies  of  the  jointworm,  emerge  in  early  Jul}  from  eggs  t  hat 
were  previously  placed  in  the  cells  occupied  by  the  jointworm.  As 
soon  as  i he  adult  parasites  emerge  they  at  once  oviposit  in  cells  con- 
taining jointworm  larvae  of  the  same  generation  from  which  they 
themselves  developed.  The  puncturing  of  these  cells  by  the  ovi- 
positor of  these  parasites,  particularly  Ditropinotus,  opens  a  way  for 

the  entrance  of  this  microscopic  mite,  and,  once  inside  of  the  cell, 
it  will  destroy  everything  therein,  whether  it  he  joint  worm  or  para- 
site. Thus  the  predaceous  mite  has  prevented  the  other  parasites 
from  controlling  the  jointworm  because  it  has  continually  checked 
the  increase  of  oi  her  parasites. 

[ClP.   118] 


22 


In  the  light  of  the  foregoing,  it  would  appear  that  the  only  way 
to  evade  the  disorder  among  human  beings  caused  by  this  mite  lies 
in  preventing  the  occurrence  of  these  two  destructive  grain  insects 
which  are  responsible  for  the  abundance  of  the  mite  itself.  There  is, 
therefore,  a  double  incentive  for  the  farmer  to  use  every  effort  to 
prevent  the  occurrence  of  these  pests  in  his  fields.  In  many  fields 
in  Ohio  Mr.  Wildermuth  found  that  more  than  one-half  of  the  straws 
had  been  attacked  by  jointworms,  and  the  damage  resulting  from  their 
attacks  amounted  to  a  considerable  percentage  of  the  farmers' wheat 
crop.    (See  fig.  13.)    In  addition  to  this — and  we  now  know  that  this 

mite  is  generally  present — his 
own  family  and  employees 
suffer  the  annoyance  of  this 
dermatitis  and  also  those  who 
attempt  to  use  mattresses  into 
which  the  infested  straw  has  en- 
tered. Thus  people  hundreds 
of  miles  away,  unaware  of  the 
presence  of  these  mites  in  mat- 
tresses,  are  caused  not  only 
great  aggravation  but  intense 
suffering  through  their  use. 

DEVELOPMENT    OF    THE    MITES. 

The  investigations  carried 
out  during  the  winter  of  1909- 
1 9 1 0  1  >y  Mr.  Wildermuth  reveal 
the  fact  that  a  period  of  from 

FIG.  13.— Reduction  in  yield  of  wheat  attacked  by  joint-  sjx  j-Q  an  indefinite  number  of 

worm  (Isosoma  trilici).    The  tube  at  left  contains  yield  '    ' 

fromliKi  heads  from  uninfested  straws;  tube  at  right  (lays  elapses  between  the  time 
contains  yield  from  100  heads  from  infested  straws.  female  emerges  fl'OlU  the  ab- 
original.) .           '        ,    ,,          '     ,,               +  -i   :  + 

domen  of  the  mother  until  it 
produces  young.     This  depends  upon  temperature. 

For  a  temperature  of  from  90°  to  100°  F.,  six  days  elapses;  for  a 
temperature  of  from  80°  to  90°  F.,  seven  days  elapses;  for  a  temperature 
of  from  70°  to  80°  F.,  nine  days  elapses;  for  a  temperature  of  from 
60°  to  70°  F.,  thirteen  days  elapses,  and  for  a  temperature  of  from 
50°  to  60°  F.,  twenty-eight  days  elapses. 

With  temperatures  lower  than  50°  F.  it  is  doubtful  if  the  mites 
would  develop.  The  periods  required  for  the  development  of  differ- 
ent females  subjected  to  the  same  temperature  are  very  uniform. 
(For  instance,  in  temperatures  of  from  70°  to  80°  F.  nearly  every 
female  produced  young  in  exactly  nine  days.)  The  life  of  the  mites 
[Cir.   L18] 


23 

varied  from  eighteen  to  an  indefinite  number  of  days  forty-three 
days  was  the  maximum  age  for  those  kepi  under  the  lower  tempera- 
tures. The  number  of  young  produced  by  a  single  female  varied 
considerably  and  variation  was  greater  among  individuals  under 
like  conditions  than  among  those  under  variable  conditions.  The 
number  varied  from  jusl  a  few  to  270.  From  3  to  8  males  were 
usually  | hi m1  need,  there  being  two  exceptions  to  this:  Iii  one  instance, 
when  the  temperature  was  between  70°  and  80°  F.,  26  males  were 
produced  and  in  another  case  a  large  number.  The  firstborn  in  manj 
cases  were  males.  The  largest  number  of  young  produced  during 
any  one  day  by  a  single  female  was  52. 

The  ideal  temperature  for  rapid  development  and  the  production 
of  the  maximum  number  of  young  was  from  70°  to  80°  F.  The  ab- 
domen of  the  female  reaches  its  maximum  size  in  about  live  days. 
The  mite  is  omnivorous,  preferring  smooth  larva'  to  hairy  ones.  A 
young  mite  can  not  enter  a  closed  tsosoma  cell.  Mites  can  live  onhj 
a  short  time  without  food  less  than  a  da\  in  all  cases  observed. 
Copulation  occupies  only  a  feu  minutes,  the  males  rarely  leaving  the 
surface  of  the  abdomen  of  their  mother.  In  the  laboratory  a  single 
Isosoma  pupa  or  larva  will  sustain  a  female  up  to  the  time  she  pro- 
duces young  and  continue  to  support  her  progeny  for  from  twenty 
to  twenty-eight  days.  In  the  held,  or  under  natural  conditions, 
one  pupa  would  probably  furnish  food  for  live  mites  for  approxi- 
mately the  same  length  of  time,  as  in  one  experiment  a  pupa  furnished 
sufficient  food  for  a  month.  The  miles  can  be  kept  alive  h\  subject- 
ing them  to  a  low  temperature  and  development  checked  for  an 
indefinite  time.  When  attacking  human  beings  they  do  not  bury 
themselves  in  the  skin  and  remain  there  as  do  the  "chiggers." 

PEEVENTIVE    AND    PROTECTIVE    MEASURES. 

Throughout  the  territory  involved  in  the  eastern  epidemic  of  this 
dermatitis,  which  was  due  to  the  excessive  abundance  of  the  Ajngou- 
mois  grain  moth,  the  evidence  recently  obtained  by  the  writer  has 
been  overwhelming!)  to  the  effeel  thai  where  wheat  was  thrashed 
as  promptly  as  possible  alter  harvesl  and  directly  from  the  shocks 
in  the  held,  almost  no  occurrence  of  this  grain  moth,  without  which 
there  would  be  no  mites,  was  observed  by  millers  and  others  han- 
dling the  thrashed  grain.  On  the  other  hand,  when  hauled  from 
the  held  and  placed  unthradicd  in  the  bam,  the  damage  from  this 
pes!  has  varied  up  to  nearly  50  per  cent,  and  has  so  affected  the 
crop  as  to  can-"  it-  rejection  by  millers,  except  where  ground  mi 
the  farmer's  order.  Here,  then,  is  a  mean-  of  protection  for  people 
who  use  or  handle  wheat   straw  grown  in  this  section  of  the  country. 

In  Ohio,  Indiana,  and  Illinois,  where  the  mite  causing  this  der- 
matitis has  increased  enormously  on  account  of  the  prevalence  of  the 

[CIr.  1 181 


24 

jointworm,  wheat  placed  in  the  barn  before  thrashing  has  been 
found  much  more  likely  to  produce  epidemics  of  this  disorder, 
although  the  difference  between  wheat  thrashed  in  the  field  and  in 
the  barn  is  not  so  striking  as  where  the  trouble  results  from  abundance 
of  the  grain  moth. 

A  careful  study  of  a  large  number  of  wheat  fields  in  central  Ohio 
by  the  Bureau  of  Entomology  has  shown  that  the  infestation  from 
the  jointworm  during  the  season  of  1909  varied  from  1  to  95  per  cent. 
Here,  too,  the  mite  was  found  generally  in  the  cells  in  the  straw 
occupied  by  the  jointworm  larvae.  It  has  been  found  that  in  central 
Ohio  September  sown  wheat  is  much  more  seriously  affected  by  the 
jointworm  than  that  sown  in  October,  and  also  that  the  infestation  is 
worse  in  both  cases  on  poor  soil  than  on  that  of  an  average  degree  of 
fertility,  and  still  less  on  good  soil.  The  infestation  is  invariably 
worse  in  fields  on  which  wheat  had  been  grown  the  previous  year,  and 
in  fields  lying  adjacent  thereto.  Fall-plowed  fields  showed  the  least 
infestation  of  all.  It  appears,  therefore,  that  moderately  late-sown 
wheat  on  good  soil  and  on  land  not  devoted  to  wheat  the  previous 
year  nor  lying  adjacent  to  such  fields,  escapes  with  the  least  injury, 
and  that  less  difficulty  with  the  dermatitis  is  experienced  where 
wheat  has  been  thrashed  from  the  field  and  as  soon  as  possible  after 
the  grain  was  harvested.  As  the  jointworm  winters  over  in  the  stub- 
ble, where  this  can  be  burned  during  fall,  winter,  or  spring,  the 
destruction  of  both  the  pest  and  the  mite  in  the  field  will  be  com- 
plete. Where  this  can  not  be  done,  much  good  may  be  accomplished 
by  raking  over  last  year's  stubble  fields  in  the  spring  and  burning 
the  stubble  thus  collected.  So  important  are  these  measures  that 
practicing  physicians  might  almost  include  them  with  their  pre- 
scriptions for  this  painful  skin  disorder. 

SUGGESTION    TO    CORRESPONDENTS. 

In  order  that  this  mite  maybe  further  studied  with  reference  to  its 
direct  relation  to  man,  all  requests  for  information  and  correspond- 
ence relating  to  derniatological  matters  should  be  addressed  to 
Dr.  Joseph  Goldherger,  passed  assistant  surgeon,  United  States 
Public  Health  and  Marine-Hospital  Service,  Hygienic  Laboratory, 
Washington,  I).  C.  All  correspondence  relating  to  entomological 
and  agricultural  matters  connected  with  epidemics  of  this  skin  erup- 
tion should  be  addressed  to  the  Bureau  of  Entomology,  Department 
of  Agriculture,  Washington,  D.  C. 

Approved. 

James  Wilson, 

Secretary  of  Agriculture. 

Washington,  D.  C,  January  11,  1910. 

[Cir.  118] 

O 


UNIVERSITY  OF  FLORIDA 


3  1262  09216  5264 


